Răspuns:
a. 25x²-16=(5x-4)(5x+4)
b. 4x²-49= (2x-7)(2x+7)
d. 64x²-81y²=(8x-9y)(8x+9y)
e. 100a²-81b²=(10a-9b)(10a+9b)
g. 36x²-49y²=(6x-7y)(6x+7y)
h. 49x²-169=(7x-13)(7x+13)